title: Metal-organic frameworks built from achiral 3-(5-(pyridin-4-yl)-4H-1,2,4-triazol-3-yl)benzoic acid: syntheses and structures of metal(II) complexes.
abstract: Using a novel flexible achiral ligand, 3-(5-(pyridin-4-yl)-4H-1,2,4-triazol-3-yl)benzoic acid (HL), four metal(II)-complexes formulated as ZnL2·2H2O (1), CdL2(H2O)2·8H2O (2) and ML2(H2O)·H2O (M = Co 3 and Ni 4) have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Complexes 1, 3 and 4 all feature a uninodal 2D layer with a 4(4)-sql topology, and two such (4,4) nets interpenetrate in a parallel manner. Complex 2 exhibits a similar 4(4)-sql topology, but no interpenetration is observed in complex 2. Among the four complexes, only complex 1 is a homochiral network, which is evidenced by the CD spectrum. In complex 1, packing of the 2D layers generates a 41 screw axis along the c direction, and two-fold axes along the a and b directions, respectively. In complex 2, the Zn(II) center lies about an inversion center, giving rise to the centrosymmetric structure of complex 2. In complexes 3 and 4, packing of the 2D units generates a 21 screw axis along the c direction in the two complexes, and an inversion center is found between two neighboring 2-fold interpenetrated layers. The work indicates that the chirality of the space group for the homochiral complex 1 comes from the supramolecular packing of the 2D layers.
authors.affiliation: Department of Applied Chemistry, College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030, P. R. China. jhlin@cqu.edu.cn jhlin@pku.edu.cn jhlin@zju.edu.cn.
authors.forename: Yun
authors.initials: Y
authors.lastname: Gong
authors.forename: Miao Miao
authors.initials: MM
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Hua
authors.forename: Jun Liang
authors.initials: JL
authors.lastname: Sun
authors.forename: Hui Fang
authors.initials: HF
authors.lastname: Shi
authors.forename: Peng Gang
authors.initials: PG
authors.lastname: Jiang
authors.forename: Fu Hui
authors.initials: FH
authors.lastname: Liao
authors.forename: Jian Hua
authors.initials: JH
authors.lastname: Lin